Papermaking machine



9, 1956 D. H. KuTcHERA 3,264,754

PAPERMAKING MACHINE Filed Aug. 1.2, 1963 5 Sheets-Sheet 1 9, 1955 D. H. KUTCHERA 3,

PAPERMAKING MACHINE Filed Aug. 1.2, 1963 5 Sheets-Sheet 2 J 1 I 1 680 68!) 68c 68d 9, 1966 11H. KUTCHERA 3,264,754

PAPERMAKING MACHINE Filed Aug. .2, 1963 5 Sheets-Sheet 5 9, W66 1:). H. KUTCHERA PAPERMAKING MACHINE 5 Sheets-Sheet 4 Filed Aug. 12, 1963 Aug. 9, 1966 D. H. KUTCHERA PAPERMAKING MACHINE Filed Aug. 12, 1963 98 FIGJZ.

5 Sheets-Sheet 5 United States Patent 3,264,754 PAPERMAKING MACHINE Don H. Kutchera, Oshkosh, Wis, assignor to Kimberly- Clark Corporation, Neenah, Wis, a corporation of Delaware Filed Aug. 12, 1963, Ser. No. 301,348 6 Claims. (Cl. 34-124) The invention relates to drier drums for papermaking machines and, more particularly, to drainage devices for such drier drums, particularly those of the Yankee type.

Paper machine drying sections generally include a plurality of drier drums, each of which comprises a cylindrical shell, spaced heads extending radially across the shell to close the open ends thereof and carrying means for journalling the shell for rotation, means for introducing steam into the interior of the shell and means for withdrawing condensate therefrom. The paper web travels serially over these driers in such a drying section. A Yankee drier drum has generally the same structural arrangement as the driers in the drying sections just mentioned; however, a Yankee drier drum is ordinarily of substantially greater diameter, and only a single one of these drums is generally used, as in connection with tissue or lightweight webs. With either type of drier drum, either the large Yankee type or the smaller type, there are, however, certain operating limitations.

Steam is admitted to the interior of each drier drum for the purpose of heating the drier shell so that it may dry the paper web traveling over the shell. Condensate forms on the inner surface of the shell; and at low speeds of the drier drum the condensate tends to remain collected within the bottom part of the drum. Above approximately 1000 feet per minute peripheral speed of the drum, at which most of the drums in present day practice are generally run, the condensate rims the interior surface of the drier shell and tends to maintain a uniform thickness layer on the interior shell surface. The condensate layer is at steam temperature but heat transfer through the water layer is relatively slow; and, therefore, inasmuch as it is between the drier shell and the body of steam in the drum, the steam is kept away from direct action on the drier shell and the transfer of heat from the steam to the shell is retarded. Preferably, therefor, for maximum heat transfer, the layer of condensate within the drier shell is kept at a minimum thickness.

The steam condensate is removed from the drum and the condensate layer is kept at a minimum thickness by siphons or dippers which receive the condensate and are connected to drain through the center of one of the drier heads. Many types of siphons and dippers have previously been proposed for removing the steam condensate. In one type, a scoop-or dipper rotating with the drum is provided on each end of the drum, and the rush of steam through the scoop atomizes the water condensate that rims the internal surface of the drier shell and draws it out with the steam. Such a scoop construction is, for example, shown in Patent 2,791,038, isued May 7, 1957. This construction, however, has the disadvantage of providing a nonuniform amount of water lining the internal surface of the drum so that parts of the web on the exterior surface of the drum are not dried as much as other parts of the web and so that the shell of the drum is distorted to some extent. If a doctor blade is used in connection with the drum for scraping the web from the drum and creping the web in doing so as is common practice in making creped tissue, the doctor blade with this shell distortion does not have the same bearing pressure against the drum for the full length of the blade which results in uneven wear on both the drum and blade as well as uneven doctoring. This arrangement for removing strips of the web result.

3,264,754 Patented August 9, 1966 ice drier condensate also has the disadvantage that it is not effective to remove enough condensate for very high speed operation; this type of condensate removal apparatus allows .25 to .3 inch of condensate on the average to remain as a layer on the interior surface of the drier shell.

Another type of condensate removal apparatus used in connection with such drums utilizes so-called full width dippers or scoops which rotate with the drum and extend for the full width of the drier drum except for spaces of 8 to 10 inches from the ends of the drum. Since the dippers have such increased lengths, the condensate is withdrawn from the drum fast enough for very high speed operation; but, due to the fact that the scoops extend longitudinally of the drum, that is, parallel with the drum axis, the scoops are effective only on longitudinal strips of the drier shell, and alternate longitudinal dry and wet Alternate longitudinal strips of the drum are hotter than the intervening strips, and there is consequent drum distortion; and, therefore, a doctor blade used with the drum and also a pressure roll, if one is used for transferring the web into the drum, bounce or move alternately in and out toward and away from the drum axis. This action of the blade and roll reduces the speed of the drum from its highest potential speed. With this arrangement, .125 inch to .1875 inch, on the average, of condensate remains in the drum.

It is an object of the present invention to provide an improved condensate removal apparatus and, more particularly, an improved siphon arrangement, for maintaining the condensate rimming the interior surface of the drier drum at a less thickness and for maintaining it more uniform in thickness so as to increase the heat transfer from the steam within the drum to the web on the exterior surface of the drum and so as to maintain the outer surface of the drum at a more uniform temperature.

As above mentioned, at relatively high speeds, as above 1000 feet per minute peripheral speed of the drum, the drier condensate tends to rim the drum completely around the drum; however, it has been found in addition that this rimming is accompanied by an oscillation of the condensate circularly about the internal surface of the drum. This oscillation is due to the smooth internal surface of the drum and increases in affect with the smoothness of this surface. The cause of the oscillation is the force of gravity which alternately retards and accelerates the water ring within the drum. The collapse or downward movement of the water ring as one part of the oscillation of the ring occurs when the centrifugal force due to rotation of the drum becomes smaller than the terrestrial acceleration or that due to gravity. A description of this oscillating movement of condensate in a steam heated cylinder is set forth in the periodical, Das Papier, volume 14, No. 10a, October 1960, pages 600-609.

It is a more particular object of the present invention to provide an improved siphon system utilizing this oscillating motion of the water in the shell and which is more efiicient to maintain the water layer thinner than prior siphon systems. In this connection, it is a still more specific object of the invention to provide drier condensate removal nozzles which move with the drum and extend axially into close proximity with the internal surface of the drum and which have their openings longer peripherally of the drum than axially of the drum, so that the effective weir length of the condensate withdrawal nozzles is greater peripherally of the drum than axially of the drum. The flow of condensate into the nozzles is thus relatively high, since the long sides of the nozzle openings are parallel with the oscillating movement of the condensate layer in the drum.

It is also an object of the invention to distribute condensate withdrawal nozzles diagonally within a drier drum so as to quite uniformly withdraw condensate from within the drum and maintain a very uniform minimum condensate thickness whereby the drum has a very uniform temperature on its exterior surface.

The invention consists of the novel constructions,

arrangements and devices to be hereinafter described andclaimed for carrying out the above stated objects; and such other objects,-as will be apparent from the following description'of preferred forms of the invention, illus-,

trated with reference. to the accompanying drawings,

wherein:

FIG. 1 is a longitudinal sectional view of a Yankee drier drum incorporating a condensate removal system embodying the principles of the invention;

FIG. 2 is a sectional view taken on line 2-1-2 of FIG.' 1;

FIG. 3 is a developed schematic View of the internal surface of the drier drum and illustrating the placement of the individual ejector nozzles and connecting headers and-branch conduits for the nozzles which are parts of the condensate removal system;

FIG. 4 is a side view on an enlarged scale of one of the nozzles;

FIG. 5 isanother side view of the nozzle taken ifrom the line 55 of FIG. 4;

FIG; 6 is a bottom viewof the nozzle;

FIGS. 7 and 8 are views corresponding respectively to FIGS. 4 and 5 and showing another, modified form of nozzle;

FIG. 9 is a pattern showing the effective condensate removal area on the inside surface of the drier drurnfor the nozzle illustrated in FIGS. 7 and 8;

FIG. 10 is a longitudinal sectional view of a Yankee drier drum incorporating a modified form of the. .con-

densate removal system of the invention;

FIG. 14 is a developed internal view-of the shell for.

the drier drum shown in FIGS. 10 and 11, illustrating the distribution of condensate ejector nozzles within the drier drum.

Like characters of reference designate like parts in the several views.

Referring now to FIG. 1, the illustrated drier drum maybe seen to comprise a thin cylindrical outer shell 10.

which is rigidly secured at its ends to a pair of relatively flat,'ring-shaped heads Hand 12 supported by a hollow central axle or shaft 13. The shell 10 is provided at each end with an integral bolting flange 14 EWhiCh is machined to mate with a similar peripheral flange 15 on the adjacent head. The. rigid attachment of the shell to each head may be made, as shown, by means of a plurality of bolts 16 inserted from the inside of theshell and drawn up by nuts on the outside of the head. Each of i the heads 11 and 12 is provided with a manhole 1 7 to provide access to the interior of the drier for assembly and maintenance.

A short cylindrical section 18 provided at its inner'end with a machined bolting flange 19 is formedintegrally;

with each. of the heads 11 and 12 and extends inwardly.

ata radial location which is intermediate the inner and.

outer edges of the head., A plurality of heavy staying members 20 extend between the heads longitudinally of the drier and are fixed with respect to the. flanges 19 by meansof flanges 21 formed on the staying membersand.

bolts 22 that extend'through the flanges 19 and 21. The purpose of the staying members 20 is to control the bowing of heads 11 and 12 to eliminate stress occurring in the shell 10-at or 'nearits connections to the heads.

The shell 10 and heads 11 and 12 are of cast construe I tion, and the central shaft 13 is also of cast construction and isformed in two halves23 and 24. 1 The halves23fi and 24 are provided with flanges 25 and 26,; and bolts 27 extend -thr0ugh;the flanges to fix the: halves-23 and '24 together. A. separator plate28 is provided'between the halves 23 and Him the purpose of providing two'sepa-= rate compartments 29 and 30 withinthe shaft .13. The shaft 13, near each-end, is provided with an enlarged.

bolting flange 31,.and each headqll and .12 is provided with a flange 32-thatmates with jthe flange 31; and the flanges 31. and 32 are fixed together by means of bolts' 33. The shaft 13 is extended .ataeach. end. to provide journals 34-for rotatably supporting the, drier in suitable bearings, a shaft: extension 35 being provided at one end of the shaft 13 for mounting a driving-gear or sprocket or the like: The shaft :13 at itsendsisprovided with bores 36 and 37 respectively in communication with theachambers 29 and 3t), and the bores 37fand 36 may respectively be utilized for providing steam under pressure intothe compartment 30 and for withdrawing the steam condensate from the compartment 29. Adrier drum substantially as so far described is disclosed in the copendingapplica tion of Malmstrom'et al., Serial No. 552,090, filed De-- cember 9; 1955., for Rotary'Pressure Vessel: (now Patent 1 3,099,543), assignedto the :same assignee asthe present.

application.

Steam under pressure is supplied to the interior of the drier drum by means of perforated nozzles 38that are in communication withthe compartment 30 and extend through the shaft 13 into'the interior cavity of the drier drum.

Condensate is removed from within the; drier drum by means of nozzles 39 110 54.? Nozzles 39 to 42 are posi-.

tioned in a plane .55; nozzles 43 to:46 are positioned in a plane 56; nozzles 47. to 50*are positioned in a plane 57" and nozzles 51 to. 54 are positioned in a plane 58. All

of the planes 55 to 58 are normal to. the. axis of. the shaft 13 and of the drier drum," and theplanese are positioned equal distances apart and somewhat closer. to the ends of the-drier :drum. The planes 55 to 58;: for example, may'be about 3 feet andi4 inches apart. and theplanes 55 and 58- may be about:2 feet and 6 inches from the ends of the drierdrum; Eachofthe nozzle's:.39..to 42.is connected by means'ofa branch Econduiti59' with a circular header 60' which in turn is connected by means of a pipe 61 with .the shaft 13 and, more particularly, with the compartment 29rwithin the shaft 13.. Thecircular header 60 is:fixed to appropriate ones of the staysv 20.? Similar circunozzles in immediately adjacent planes are staggered and areplocatedmidway with respectto the nozzles in the other plane. .The nozzleszinathe developed-plan-yiew of the internal surface of.;the drumwshown in FIG., 3 are thus located on therdiagonals 68a 68b; etc.

The nozzle=39 (and each :of the othernozzles 40 :to 54) may be=in the formsillustrated in FIGS. :4 and 5.

The' nozzle. 39,?as illustrated, comprises: a hollow'casing' 69 whichhas on one end an internally threaded enlarged. portion 70 by means' of which the nozzle is fix'ed on the 1 associated pipe, 59. The nozzle on its other end has a cylindrical face portion or surface, '71 that faces and is located adjacent to the internal cylindrical, surface of the shell.10;'and, 'as illustrated in FIG. 5, the: nozzle 39 has two obliquely extending face portions 72 and 73' connected with the; face portion 71'. As will be observed from FIG. 4, the casing 39flares outwardly (toward the internal surface .of the shell 10) inone maj'or plane and, as willibe observedfrom FIG; 5, itv tapers inwardly in the other major plane so that the surface 71 is relatively long and narrow. The nozzle 39 is disposed so that the long dimensions of the surface 71 are parallel with the plane 55 for the nozzle so that the nozzle in general, as

far as possible, is within the plane 55.

A pair of partitions 74 and 75 are provided which are bounded by the surface 71 so as to provide elongate openings 76, 77, and 78 in the surface 71. As will be observed from FIGS. 4, and 6, each of these openings is substantially longer in the circumferential direction of the drum than the width of each opening in the axial direction of the drum at the outer termination of the openings on the surface 71 and the openings are spaced by the partitions; and, therefore, the length of the pattern of the three openings on the surface 71 is more than three times the width of the pattern, measuring the length of the pattern from the remote ends of the openings 76 and 78 and considering the width to be the width of one of the openings. These elongate openings also extend parallel with the plane 55 for the nozzle. An aspirator opening 79 extends through a side of the casing 69, as illustrated. The nozzles to 54 are similar to the nozzle 39, and the surface 71 and the openings 76, 77, and 78 in the nozzles 40 to 54 all extend parallel with the respective planes to 58 for purposes to be hereinafter more particularly described.

The partitions 74 and 75 may, if desired, be omitted, although they are preferably provided for the purpose of producing turbulence in the mixture of steam and condensate that flows through the openings 76, 77, and 78. If the partitions 74 and 75 are omitted, a single elongate opening will thereby be provided in the surface 71 leading interiorly of the casing 69, and this elongate opening also has its sides parallel with the particular plane 55 to 58 in which the nozzle is located.

Other nozzles having their inlet openings close to and facing the interior surface of the drum, with the long sides of the openings disposed generally in the planes 55 to 58, may be used instead of the nozzle illustrated in FIGS. 4, 5, and 6. Such a modified nozzle is illustrated llIl FIGS. 7 and 8 and comprises a hollow casing 80 which is relatively long in one direction and relatively narrow in the other direction. The casing 80 is provided with a threaded opening 81 by means of which it is in screw threaded engagement with the associated pipe 59, and the casing 80 is provided with an elongated opening 82 at its other end. A plate 83 is disposed over the opening 82 and is fixed with respect to the casing 80 by means of screws 84. The plate 83 has an outer cylindrical surface 85 that is located adjacent to the internal surface of the drum, and round openings 86, 87, and 88 are disposed in the plate 83. The opening 87 extends directly on the axis of the pipe 55 so as to be normal to the internal surface of the drum, and the openings 86 and 88 slant outwardly with respect to the opening 87 whereby the overall etfect of the three round holes 86, 87, and 8-8 is a pattern on the surface 85 that is more than three times longer in the circumferential direction of the drum than the width of the pattern in the axial direction of the drum, the length of the pattern in the circumferential direction being measured from the remote edges of the openings 86 and 88 and the width being the diameter of one of the openings, and the effect also is an elongate pattern 89 on the internal surface of the drier drum. The elongated plate 83 has its long sides extending parallel with one of the planes 55 to 58, and the pattern 89 on the internal surface of the drier drum, therefore, is elongated in the direction of the plane. An aspirator opening 90 is provided in the side of the casing 80 and is comparable to the aspirator opening 79 in the nozzle illustrated in FIGS. 4 to 6.

The illustrated drier drum is mounted in a papermaking machine in a position to receive the web from the felt section of the machine and is rotatably driven so Cir as to pass the web over the drum and dry the web. The web may be applied by any suitable mechanism to the outer surface of the drier drum, such as by means of a pressure roll (not shown) having a nip with the drier drum, and the web may be removed from the drier drum by any suitable means such as a doctor blade (not shown) which functions to crepe the web from the drum. Steam under pressure is supplied to the bore 37 and to the compartment 30, and the steam is released into the drum by means of the nozzles 38. The steam functions to heat the drum so as to dry the web and in giving up its latent heat, the steam condenses on the internal surface of the shell 10. Assuming that the speed of the drier drum is above 1000 feet per minute, for example, the water condensate rims the internal surface of the shell 10, and as has been previously described, this water condensate also oscillates back and forth circumferentially of the drum. The nozzles 39 to 54 have their cylindrical surfaces 71 in close proximity to the internal cylindrical surface of the shell 10, with these surfaces being spaced preferably from A; inch to A2 inch from the internal shell surface. The long dimension of the surface 71 of each of the nozzles extends in the same directions as the planes 55 to 58, namely, circumferentially of the shell, and this disposition of the nozzles is for the purpose of utilizing the oscillating circumferential motion of the condensate just described for more effectively removing the condensate from the drum. The nozzles 39 to 54 are fixed with respect to the drum and this oscillating motion thus is the only relative circumferential motion that there is between the nozzles and the condensate rimming the internal surface of the shell 10.

The long sides of the openings 76, 7'7, and 78 act as weirs extending parallel with the direction of condensate movement as it oscillates circumferentially of the shell 16. The steam atomizes in the vicinity of the openings '76 to 78 and passes through the openings and in doing so it draws condensate along with it through the openings. The steam-condensate mixture passes through each of the nozzles 39 to 54, the circular headers 65) to 64 connected with the nozzles, and the pipes 61, 65, 66, and 67 into the compartment 29 and through the bore 36 for suitable disposition. Due to the fact that the long sides of the openings 76 to '78, and the long sides of the resulting steam withdrawal pattern on the internal surface of the shell 10 due to the combined effects of the openings 76 to 78, extend circumferentially, appreciably more condensate is withdrawn by the nozzles 39 to 54 than would otherwise be the case if the nozzles were turned through The improved condensate withdrawal action of the elongated nozzles 39 to 54 disposed to extend circumferentially of the drum is due to the fact that condensate may enter a nozzle only when the condensate flows along in the same direction or toward an edge of a nozzle opening. One of the short rounded ends of each of the openings 76 to 78, with the surface 71 extending circumferentially of the drum, does constitute an active end of each of the openings since the condensate in its circumferential oscillation flows toward this rounded end, but the other end does not constitute an active end; and, in any case, the relatively short ends are not very effective compared to the long sides of the openings 76 to 78. Since these long sides extend parallel to the direction of movement of the condensate in its oscillating motion, both sides are simultaneously effective as weirs tending to withdraw the condensate. Due to the disposition of the nozzles with the elongated surface 71 extending circumferentially of the drum, the weir length for combined steam and condensate passage has been effectively increased to include both the two long sides of each opening 76 to 78 and one of the short ends of each nozzle opening depending on the particular circumferential direction in which the condensate is flowing at the time.

The nozzles 39 to 54 are preferably disposed on diagonal lines 68a to 68c (see FIG. 3) for providing a Well 7 distributed pattern of condensate withdrawal from the inside; of the shell 10. Sucha disposition of .nozzles has been found to be more effective in providinga uniform layerv of condensate within the shell. As will be understood, it is not only desirable to have the layer of condensate in the drum very thin, but it is even more important to have the layer of condenstae uniform, in order to provide uniform drying of the Web, The. aspirator opening 79 in each. of the nozzles ;39 to 54 functions to allow a free flow of a thin stream of, steam directly into the casing 69. This free flow of steam functions to help to keep the, piping .connected with the nozzles free vfrom blockage by water condensate.

The nozzle illustrated in FIGS. 7, 8, and 9 operates substantially in the same manner as the nozzle illustrated in FIGS.- 4 to 6 for breaking up the water'and atomizing it: The ,patern 89 and thegeneral pattern of the vholes 86 to 88:extend circumferentially and provide the increased weir action similar to that provided by the openings 76 to 78.

The drier drum illustrated in FIGS; 10 and 11 is very similar to that illustrated in FIGS.- 1 and 2. The drum illustrated in FIGS. .10 and 11 has drum ends 11a and 12a supporting a shell 10a and struts a extending between the flange portions 1861 of the drum ends. The ends 11a and 12a are fixed with respect to a shaft 13a which is similar to the shaft 13 except that a partition 91 isdisposed in one of the parts 23a for providing'the separated steam compartment, a and condensate comp-art ment 29a. Nozzles 38a similar to the=nozzles 38 are providedfor injecting steam under pressure into the drum.

The condensate removal system for this drum comprises a plurality of nozzles 92,.each of which has'three openings 93, 94, and 95 .in a cylindrical surface 96 that is positioned closely adjacent. to and conforms to the :inner cylindrical surface of the shell 10a. Each of the nozzles 92.comprises a hollow casing 97, which, similarly to the nozzle casing 69 illustrated in FIGS. 46,- tapers. in one cross section and flares in :the other cross section. An elongated orifice plate 98'is fixed with respect to the casing 97, and the openings 93, 94, and 95 are provided in the plate 98. The opening. pattern provided by the openings 93 to 95, like that of the openings 76' to 78, extends circumferentially of the adjacent shell'10aa The nozzles 92 are connected by means of branch pipes 99 with a circular header100. The branch pipes 99 and circular header 100 are supported by means of suitable brackets with respect to the stays 20a, as illustrated- The circular header 100 has both of its ends .101 and 102' extending into and connected with the condensate ,exhaust compartment 20a of the shaft 23a.

As illustrated in'FIG. 14, which is a developed view of the inside of the drier shell 10a, the nozzles 92;:like

the nozzles 39 to 54 in the first embodiment, are disposed on diagonal-s 103a, 103b, etc. to assure that the nozzles 92 provide uniform coverage and condensate removal effect for the inside surface of the shell 10a.

The circular header 100 is made of a plurality of areshaped segments 104 in addition to the ends 101 and 102. The ends and segments have flanges on their ends which may be bolted together in order to form the complete header 100. The header 100 having both of its ends connected to the condensate removal compartment 29:: assures that the condensate may always reach the compartment, since it has two paths by means of which it can do so. The circular header 100 is formed by means of the segments 104 so that it can be installed within the drier drum by moving it piece by piece through the manholes 17a.

It is recognized that there may be unbalanced friction pressure drops and unbalanced static pressures in various places in the illustrated condensateremoval systems. In order that the systems may be balanced and so thatthere are uniform quantities of steam and condensate flowing through. the nozzles, thefollowing provisions may be per minute.

8; made: 1) the; diameters of the nozzle openingsmaybe changed by redn'lling; (2) the clearance between one or more of the nozzles and: the shell may be changed to correct the flow in' thenozzles; (3') vent holes or orific'esmay be provided;in the. exhaust headers or nozzle pipes to increase the steam flow in certain areas; (4) orifices may be instahlediin' t-he=headers or nozzle. pipes to balance pressure drops .or (5) thefiinternal: {diameters of the headers mayv be decreased or increased, particularly at the flange connections for example in the condensate removal .system illustrated in FIGS. 10land 11. It is obvious that the nozzles that are fartherfrom-the condensate compartments in the central shaft of the drum have more of a pressure drop;between them and the compartment thando the others, and thevmost obviousexpedient for overcoming this condition is to space some of the nozzles farther from the internal surface of the drum than the other nozzles; As another change, one or more prior art scoops (such as is illustrated in the patentrto Armstrong 2,892,264, issued on ilnnez30, 1959, for example) may be installed in connection -withione' or more of the nozzles above described totrernove puddles of condensate collected in the lower parts of the drums when the drums are driven at sl-owspeeds; suchas on ofl hours when no paper is being made. K

The nozzles illustrated anddescribcd. which have their opening patterns extending circumferentially of the: drum provide increased Weir edge lengths across which steam flows from the drum to break up and .atomize the water condensate for eflectively withdrawing more of the con- Y densate from the drum,'de'creasing the. thicknesso'f the layer of condensate in the drum, and increasing the'heat' transfer :from thelsteam to the exterior surface of the drum. 1 The double ended circular-header in the form x of the invention illustrated vinFIGS; l0 and .11 materially shortens the branch pipes from each. of. the individual nozzles and assures that the pipes donot become plugged It will be noted thatrthe header 7 ran isclose to the interior surface of the drum so as to 1 materially shorten the individuall'branch pipes, to each of with water condensate.

the nozzles and help in assuring that the branch pipes do not become clogged with watercondensate.v

The nozzles are preferably uniformly spaced from each other on diagonalswith-in the drum, and the nozzles thus .are quite .etfective for not only maintaining the conden-' sate layer thin but also for-maintaining it uniform on the inside surface of. the drum. A minimum desirablespacing between the nozzles is 24 inches, in which case each nozzle would have an effective area .of ZlbOlltsfOLlI' square feet of coverage withia conventional Yankee drier drum having an internal shell surface of about 550 square feet,- for example. This spacing of nozzles would require about nozzles for this size of drum and could be very desirableforz high drier speeds, such as 4000 to 5000 feet For lower" speeds, however, larger spacings of nozzles are satisfactory. With the illustrated drums,

for example, there are spacings of 4 to 5 feet between:

nozzles, and only va total of 16=nozzles is used.- The greater number of nozzles mentioned above, as is appar& cut, would require more nozzle .lI'OWS. andmore nozzles within each row.= Although the depth of the condensate rimming the drum is a function of the number of nozzles, it is, of course, desinable't-o keep the numberof nozzles: at a .minimumdue to the costof additional nozzles.

The nozzles are preferably set normal to the internal surface of the drier; drum. Their clearance from this surface, however, .is: not critical as long as the steam scours the internal. drum surface clean and each nozzle provides sufllcient flow'area for: steam: and condensate. By making the nozzles as narrow as possible circumferentially of the drum, hot spots due to the nozzles are kept as small as possible. and la uniform condensate flow pattern is promoted The end faces, of the nozzles facing the internal drum surface are' prefer-ably, but are not necessarily, cylindrical and equally space for their full areas from the inner drum surface. These cylindrical nozzle surfaces can in fact be dispensed with and in lieu of the surface 71 shown in FIGS. 4 to 6, for example, three simple pipes could be used having elongated openings in them, with the end edges of the pipes being equally spaced with respect to the inner drum surface.

Although constructions have been illustrated utilizing nozzles that travel along with the drier drums, particularly since the illustrated drums are of the stayed type having the tie stays and 20a holding the drum ends together, obviously the elongated nozzles according to the invention could instead be used if they were stationarily held With-in a rotatable drier drum. In this case, not only would the oscillating circumferential motion of the condensate be utilized in connection with the long weir edges extending circumferentially of the drum, but the motion of the condensate in rimming the drum and traveling with the drum would also be utilized in connection with these circumferentialtly extending long weir edges.

I Wish it to be understood that the invention is not to be limited to the specific constructions, arrangements and devices shown and described, except only insofar as the claims may be so limited, as it will be apparent to those skilled in the art that changes may be made without departing from the principles of the invention.

What is claimed is:

1. A rotatable drier drum having an inner surface which is cylindrical and smooth, a steam supply connection for directing steam into the drum, a plurality of water condensate removal nozzles in said drum distributed about the inner surface of the drum, each of said nozzles having an opening pattern which faces and has a termination closely adjacent to the inner drum surface and which at said termination has a length in the circumferential direction of the drum that is more than three times greater than the width of the pattern in the axial direction of the drum, and water conduit means connected with said opening pattern in each of said nozzles for carrying water condensate from the drum.

2. A rotatable drier drum having an inner surface which is cylindrical and smooth, a steam supply connection for directing steam into the drum, a plurality of water condensate removal nozzles in said drum distributed about the inner surface of the drum, each of said nozzles having an opening pattern which faces and has a termination closely adjacent to the inner drum surface, said opening pattern comprising a central opening extending in a direction normal to the inner drum surface and two side openings located along with said central opening in a plane perpendicular to the drum axis and diverging with respect to said central opening so as to provide an opening pattern at said termination which has a length in the circumferential direction of the drum that is more than three times greater than the width of the pattern in the axial direction of the drum, and water conduit means connected with said openings in each of said nozzles for carrying water condensate from the drum.

3. A rotatable drier drum having an inner surface which is cylindrical and smooth, a steam supply connection for directing steam into the drum, a plurality of water condensate removal nozzles in said drum distributed about the inner surface of the drum on lines that are diagonals with respect to the axis of the drum and with at least three nozzles being on each diagonal, and water conduit means connected with said nozzles for carrying water condensate from the drum.

4. A rotatable drier drum having an inner surface which is cylindrical and smooth, a steam supply connection for directing steam into the drum, a plurality of water condensate removal nozzles in said drum disributed about the inner surface of the drum on lines that are diagonals with respect to the axis of the drum and With at least three nozzles being on each diagonal, each of said nozzles having an opening pattern which faces and has a termination closely adjacent to the inner drum surface and which at said termination has a length in the circumferential direction of the drum that is more than three times greater than the width of the pattern in the axial direction of the drum, and Water conduit means connected with said opening pattern in each of said nozzles for carrying water condensate from the drum.

5. A rotatable drier drum having an inner surface which is cylindrical and smooth, a plurality of nozzles in said drum each of which has an opening facing and terminating closely adjacent to the inner drum surface and which are distributed in a uniform pattern about the inner surface of the drum, said drum comprising an axle having two compartments in opposite ends of the axle, one of said compartments being adapted to have steam connected thereto and having an opening in a side thereof for supplying steam to the interior of the drum, a circular header pipe extending circularly within the drum and having both of its ends connected to the other compartment in said axle, and a plurality of branch pipes connecting said circular header pipe with said nozzles whereby the nozzles may collect water condensate from the drum and the water condensate may be carried by said branch pipes and circular header pipe to said other compartment for disposition of the water condensate.

6. A rotatable drier drum having a plurality of nozzles in said drum each of which has an opening terminating closely adjacent to the inner drum surface and which are distributed in a uniform pattern about the inner drum surface, said drum comprising an axle having a steam inlet duct and a condensate outlet duct, said steam inlet duct being arranged. to supply steam to the interior of the drum, a circular header pipe extending circularly Within the drum and having both of its ends connected to said condensate outlet duct in said axle, and a plurality of branch pipes connecting said circular header pipe with said nozzles whereby the nozzles may collect water condensate from the drum and the water condensate may be carried by said branch pipes and said circular header pipe to said condensate duct for disposition of the condensate.

References Cited by the Examiner UNITED STATES PATENTS 2/1934- Dukes 34-125 5/1955 Garrett 34124 FOREIGN PATENTS 2,961 3/1885 Great Britain. 

1. A ROTATABLE DRIER DRUM HAVING AN INNER SURFACE WHICH IS CYLINDRICAL AND SMOOTH, A STEAM SUPPLY CONNECTION FOR DIRECTION STEAM INTO THE DRUM, A PLURALITY OF WATER CONDENSATE REMOVAL NOZZLES IN SAID DRUM DISTRIBUTED ABOUT THE INNER SURFACE OF THE DRUM, EACH OF SAID NOZZLES HAVING AN OPENING PATTERN WHICH FACES AND HAS A TERMINATION CLOSELY ADJACENT TO THE INNER DRUM SURFACE AND WHICH AT SAID TERMINATION HAS A LENGTH IN THE CIRCUMFERENTIAL DIRECTION OF THE DRUM THAT IS MORE THAN THREE TIMES GREATER THAN THE WIDTH OF THE PATTERN IN THE AXIAL DIRECTION OF THE DRUM, AND WATER CONDUIT MEANS CONNECTED WITH SAID OPENING PATTERN IN EACH OF SAID NOZZLES FOR CARRYING WATER CONDENSATE FROM THE DRUM. 